The long-term objective is to develop a theory of brain function that explains the dynamics of cerebral cortex in the operations of sensation, perception, decision, and response. The long-term result is expected to be a set of procedures, based on a new understanding of the fundamental physical "code" underlying mental processes, that would allow precise clinical evaluation of malfunctions of the cerebral cortex in information processing disorders such as schizophrenia. The immediate aim is to extend theories and analytic methods of mass neural action developed in mammalian paleocortex to scalp-recorded human event-related potentials (ERPs). State-of-the-art recording and analysis methods will facilitate the attempt to uncover basic patterns of mass neural activity that carry task-specific information processed by the human cerebral cortex. Neuroelectric data will be recorded from an array of 128 electrodes placed on the scalp of human volunteers making split-second discriminations of somatic stimuli. The analysis will focus on a search for the borad-band, high-frequency, spatiotemporal "carrier wave" hypothesized by theory, and found in animal studies, to be the manifestation of task-related mass neural processing. Extensive preprocessing will filter out contaminants, and reduce volume conduction distortion of the potentials. Single-trial spatial amplitude patterns, constructed for a range of temporal bandpass filters with differing center frequency and bandwidth, will be optimized based on their ability to correctly discriminate the three somatic stimulus classes presented in this task, and the three response types elicited by the stimuli. It is expected that the hypothesized "carrier wave" will be mapped and described, that the underlying cortical neural activity patterns will be deduced, and that theories describing the generation of these neural activity patterns will be enabled.